What was found
APU HAD AUTO SHUTDOWN DURING PACKS ON AND ELEC LOAD FAULT LGT ILLUM AND A STRONG SHORT CIRCUIT ODOR. APU SECOND START WAS UNSUCCESSFUL IAW AMM 05-51-56 PAGE 201, INSPECTED CABIN BY ODOR AND IAW AMM 21-00-21, PAGE 201, CHECKED AIR CONDITIONING PACKS AND NO ODOR WAS FOUND AROUND THE CABIN AND COCKPIT. PERFORMED APU ECB BITE AND FOUND APU START TRU, AND FOUND APU STAR TRU C/B POPPED OUT. TRANSFERRED APU TO DMI 455 IAW MEL 49-11-1 CAT C. THE APU WAS REMOVED AND REPLACED IAW AMM 49-11-01 PAGE 401.